If the Ksp for CaF2 is 5.6 x 10-5 what is the solubility of CaF2?

Question

If the Ksp for CaF₂ is 5.6 x 10-5 what is the solubility of CaF₂?

	A. 0.048 M
	B. 0.024 M
	C. 2.15x 10-5 M
	D. 4.30 x 10-5 M

Answer 1

CaF2(s) <==> Ca2+(aq) + 2F-(aq)

Ksp = [Ca²⁺][F-]²

Let x = [Ca²⁺] and the 2x = [F-]

5.610^-5 = (x)(2x)² = 4x³

x = 2.4x10^-2 M (Answer B)